Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

MODERATE avalanche danger will exist today due to loose wet and wind slab avalanche problems.  Human triggered avalanches remain possible.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    As daytime warming occurs, loose wet avalanche activity will become possible on all aspects and elevations.  Overnight cloud cover with some areas below 7500' having above freezing temperatures could cause loose wet avalanches to occur earlier than areas that had a good overnight refreeze.  Large loose wet avalanches are possible that involve the recent storm snow and potentially the underlying wet snow.  Size D2 loose wet avalanches occurred yesterday that traveled long distances.  

    Monitor snow surface conditions and warming.  Roller balls and pinwheels will be an indication that the snow surface is losing strength and larger loose wet avalanches could occur. 

     

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Recently formed wind slabs could still be reactive on NW-N-NE-E-SE aspects in near and above treeline terrain.  Due to the wet and heavy recent storm snow, most wind transport is limited to areas above 8000' where colder snow exists.  Continued moderate to strong SW winds will transport snow until winds decrease later today.  Daytime warming could further weaken these newly formed wind slabs. 

    Look for evidence of recent snow transport including blowing snow, new cornice formation, and wind pillows.  Use terrain to avoid areas of concern.

Avalanche Discussion

*  Multiple loose wet avalanches were reported from Donner Peak and Andesite Peak in the Donner Summit area up to size D2.  These avalanches involved all the new storm snow and some of the underlying wet snow.

*  Heavy storm snow existed above wet snow in the Echo Lakes area and the Donner Summit area up to 8000'.  Minimal wind transport was observed below 8000' due to the heavy storm snow.  Snow level stayed around 7000' throughout the day.

Regions covered